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%I #11 Feb 27 2023 08:38:09
%S 1,4,44,472,63944,799416,137263244,1860249448,357974884304,
%T 1036802274574832,15013817777670240,47192717951302358280,
%U 10360599532843724350568,154361699651510683256944,34589385964787861980005536,118349529407778159289257602576
%N (1/n)*(binomial(2n,n)-2^n) as n runs through the primes.
%p a:= n-> (p-> (binomial(2*p, p)-2^p)/p)(ithprime(n)):
%p seq(a(n), n=1..20); # _Alois P. Heinz_, Feb 27 2023
%Y Cf. A000040.
%K nonn
%O 1,2
%A _Benoit Cloitre_, Oct 15 2003